KR100287111B1 - Mold tool heated momentarily with flames of gas fuel and molding method using such mold tool - Google Patents

Abstract

PURPOSE: A momentary heated mould with gas flame is provided to heat up the mould tool most quickly and cool down it most quickly again by using the gas flame for the mould tool heating by keeping in space without supporter, and does not pollute the mould tool surface. CONSTITUTION: Needle hole gas supply units is provided in order to supply the gases into the room between the open mould parts(1) without any restriction. The diameter of needle hole is less than the dimension of non flow thickness of molten resin indicated for the component so that the gases pass it freely on one hand and molten resin does not pass it on the other hand. The needle hole can be made directly on the mould tool base but for the convenience and cost effectiveness of numerous needle holes, the assembling unit is devised. The multiple gas supplying unit is an alternative gas supplying unit for the mould tools which do not allow the needle hole gas supplying unit or have enough space for it. The diameter of the hole of multiple gas supplying unit can be big as wished because it does not contact the molten resin during the processing. In order to minimize the mould surface heating time with momentary heated mould with gas flame, the gas flame must be kept inside the room between the properly closed mould parts(1).

Description

Mold tool heated momentarily with flames of gas fuel and molding method using such mold tool}

Molds and molding methods generally relate to plastics technology. Plastics technology consists of three technical fields: raw material production technology, molding machine technology and mold technology.

The quality and cost of production of the final plastic molded part are greatly influenced by each of these three technologies. Among them, mold technology relies more on trial and error experience than on theoretically established standardized methods. The fundamental reason is that the temperature of the mold is not raised properly. When the glass transition of the resin using the temperature of the plastic molding mold is heated higher than the temperature, it has been found that the combination of all plastic moldings that could not be avoided by the conventional method can be solved. Several methods have been proposed to improve the quality of non-painted television housings or compact discs. For example, mold heating method using high frequency, electric heating method, heat insulation coating method on the mold surface and ultra-fast injection molding methods have been devised for mass production. However, all of the above methods did not apply to commercial production due to the increased production cost and long production time.

The most difficult aspect of the mold technique is how to heat and cool the mold to the desired temperature as quickly as possible. It is essential to heat molds without increasing costs to produce high quality plastic molded parts.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a mold and a molding method using a mold, and more particularly, to an instant heating mold using a gas fuel flame and a molding method using the same.

The features and other advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

1 is a schematic view of a mold for instantaneous heating using gaseous fuel according to the present invention.

Figure 2 is a block diagram showing a general structure of a mold for instant heating using a gas fuel according to the present invention.

3 is a view showing a micro-pore gas fuel supply device.

4 is a view showing a gas flame shield, FIG. 4A is a front view of the core portion of the mold, and FIG. 4B is a view showing a cavity portion of the mold.

5 is a view showing a connection structure of the gas fuel supply device and the cooling water pipe.

Figure 6 is a graph comparing the temperature of the molten resin and the mold surface between the conventional injection molding method and the injection molding method according to the present invention, Figure 6a is a temperature difference between the mold surface and the molten resin in the conventional injection molding method Figure 6b is a view showing the temperature difference between the surface of the mold and the molten resin in the injection molding method using the instantaneous heating mold using the gas fuel flame according to the present invention.

Figure 7 is a graph comparing the heating time of the closed flames and open flames.

8 is a computer simulation graph comparing the resin flow length of 40 ℃ and 190 ℃.

9 is a view showing the general structure of the composite gas supply apparatus having a moving support, Figure 9a is a view showing the composite gas supply when the mold is open, Figure 9b is a mold inside when the mold is completely closed Figure showing a composite gas supply device entered.

* Drawing reference

1. Mold body (movable body, fixed body)

2. Gas fuel supply device

3. Gas fuel supply pipe

4. oxygen or air supply pipe

5. Micro-pores for supplying gaseous fuel into the mold

6. Space to maintain gaseous fuel flame between two mold bodies

7. Cooling water pipe

8. Flamebreaker

9. Nozzle of injection machine

10. Clamping Device of Injection Molding Machine

11. Fine study

12. Fasteners to fix micro-study to mold

13. ignition

14. Inside of the mold body

15. Spring

16. Moving support

17. Compound gas supply device

The present invention is to effectively control the temperature of the mold to the desired temperature and to be filled into the mold in a stable state without any resistance when the molten resin flows while the temperature of the mold surface is heated to the temperature of the molten resin or more. It provides a method of molding a plastic having a perfect appearance.

Flames using gaseous fuel can be held in the air without a support, are easily ignited by a flame, and can be extinguished by blocking gaseous fuel. This is the most convenient, simple and inexpensive way to quickly heat and cool the mold. In order to freely control the gas fuel flame for heating the mold surface, the present invention provides a mold having a micro-porous gas fuel supply device or a composite gas supply device.

Accordingly, an object of the present invention is to provide a mold for instantaneous heating using a gaseous fuel flame and a molding method using the same. In order to achieve the above object, the present invention provides a gas fuel supply device for supplying gas fuel into the first space formed between the mold body, oxygen supply device for supplying oxygen into the second space formed between the mold body and A mold body having ignition means for igniting gaseous fuel and oxygen; A gas fuel supply pipe connected to the gas fuel supply device and closed when fuel is supplied to the end; Provided is a mold for instant heating using a gaseous fuel flame composed of an oxygen supply pipe connected to the oxygen supply device and closed when oxygen is supplied to the end.

Another embodiment of the present invention is formed between the gas fuel supply device and the inner surface of the mold body and the supply port having a size relatively smaller than the size that the molding material can flow between the oxygen supply device and the inner surface of the mold body. do.

In another embodiment of the present invention, the gaseous fuel supply device and the oxygen supply device are formed in a slide core that can be exposed when the mold body is open and concealed when the mold body is closed.

According to the invention, the step of supplying gaseous fuel and oxygen to the space formed between the mold body; Igniting the supplied gaseous fuel and oxygen; Heating the inner surface of the mold body instantaneously to a desired temperature using a gaseous fuel flame; It further provides a molding method using a mold for instantaneous heating using a gaseous fuel flame consisting of supplying the molding material into the inner cavity of the mold and forming the material in the mold.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic view of a mold for instantaneous heating using a gas fuel according to the present invention, showing that the gas fuel supply device 2 is attached to a lower part of a conventional mold. The mold is attached with a gas fuel supply pipe 3 connected to the mold body to supply gas fuel and an oxygen or air supply pipe 4 connected to the mold body to supply oxygen or air. In addition, the nozzle 9 of the injection molding machine and the clamping device 10 of the injection molding machine are attached to the mold.

2 is a view showing the general structure of the instantaneous heating mold using the gas fuel according to the present invention, the gas fuel supply pipe (3), oxygen or air supply pipe (4), micropores (5), cooling water pipe (7) and The space 6 and the flame film 8 between the two molds are shown. When gas fuel and oxygen or air are supplied to the space 6 between the two molds through the micropores 5 and ignited, the flame is kept constant inside the mold to heat the entire mold surface.

3 shows a micro-porous gas fuel supply device that gas fuel passes but molten resin does not pass, which consists of a micro-pore 11 and a fastener 12. By fixing the micro-holes 11 processed by the micro-pores (5) using the fastener 12 to be connected to the gas fuel supply pipe 3 and the oxygen or air supply pipe (4).

4 shows a flame film 8 for maintaining gas and gas flame in a space formed between two molds. The flame film 8 prevents gaseous fuel flame from escaping to the outside of the mold, thereby improving the thermal efficiency of heating the gas flame to stay only inside the mold, and preventing gas flame from being transferred to flammables outside the mold. It acts as a stabilizer. 4A is a front view of the core portion of the mold, and FIG. 4B shows a cavity portion of the mold.

FIG. 5 is a view illustrating a connection structure between the gas fuel supply pipe 3 or the oxygen supply pipe 4 and the cooling water pipe 7, and shows that the two pipes use the same path. When the gas fuel supply pipe or the oxygen supply pipe 4 uses the same path as the cooling water pipe using the suction force, the valve connection is used to switch the supply of the two fluids using the valve. Install a valve to switch the supply of gaseous fuel and cooling water in the upper part of the mold, and install a valve for discharging the cooling water in the lower part of the mold, connect it to the suction pump, and connect the two valves with the electric circuit of the injection molding machine. Only fuel and oxygen or air are supplied into the mold's internal space, and during cooling the coolant is supplied and the discharge valve opens. Therefore, the cooling water does not leak through the micropores.

Figure 6 is a graph comparing the temperature of the molten resin and the mold surface between the conventional injection molding method and the injection molding method according to the present invention, Figure 6a is a temperature difference between the mold surface and the molten resin in the conventional injection molding method 6b shows the temperature difference between the mold surface and the molten resin in the injection molding method using the instantaneous heating mold using the gas fuel flame according to the present invention. As shown in Figure 6a and 6b, in the conventional injection molding method there is a significant difference between the temperature of the molten resin and the surface temperature of the mold when the molten resin is injected into the mold, the gaseous fuel according to the present invention In the method of forming the mold by the instantaneous heating mold using flame, the temperature of the molten resin and the surface of the mold surface are maintained at the same level in all processes.

7 is a graph comparing the heating time of closed and open flames, where the heating time is related to the mold wall thickness, the fuel is acetylene and the mold material is carbon steel. In order to effectively heat the mold surface, the thickness of the mold surface is better. The mold used in the conventional injection molding method requires a thickness of about 15 mm, but according to the present invention, since about 30 times lower, the mold can withstand the injection pressure even with a thickness of the mold wall surface of about 5 mm.

8 is a computer simulation graph comparing resin flow lengths of 40 ° C and 190 ° C, and the flow length at 190 ° C is 30 times the flow length at 40 ° C. That is, when the mold surface temperature is raised to the same level as that of the molten resin, the flow length of the resin is increased by about 30 times compared with the conventional one. For example, when the resin was ABS, the thickness of the molded article was 1.0 mm, which was half of the general case.

FIG. 9 is a view showing the general structure of the composite gas supply device having the movable support 16, and FIG. 9A is a view showing the composite gas supply device 17 coming out of the mold surface when the mold is open. 9b shows the composite gas supply device 17 that has entered the mold when the mold is completely closed.

Instantaneous heating mold using the gas fuel flame and the molding method using the same according to the present invention is an ideal plastic molding method so that the surface temperature of the mold is controlled to the desired temperature or more than the molten resin temperature, the molten resin is filled into the cavity without flow resistance to be. In addition, the defects that are always seen in conventional plastic molded products are gate marks, weld lines, flow marks, and surface roughness due to the nonuniformity of the stress and temperature of the molded products. It provides a high gloss molded article surface. The above defects are generated when hot melt is filled into the cavity of the mold between the cold surfaces. In particular, the time that the mold surface is heated to 300 ℃ does not exceed 10 seconds, by heating only the mold surface with a gas fuel flame so that the entire mold surface is continuously heated regardless of the mold temperature and the size or complexity of the mold.

In particular, the two mold bodies are spaced several mm to 30 mm apart so that the gas fuel flames touch the mold surface and only the surface of the mold touches when molten resin flows from the injection molding machine into the mold. Also, it is possible to instantaneously heat up to a high temperature of about 300 ° C, and even in the case of a large mold or a deeply curved mold, molten resin does not flow, but gaseous fuel passes through the micropores of the size of the mold and the desired position. It can be installed on the mold to control the gas fuel flame to the desired position and amount regardless of the size and shape of the mold to heat the entire mold surface to a uniform temperature.

Therefore, when the molten resin generated in the prior art is filled into the mold, various appearance defects caused by quenching while contacting the mold surface at a lower temperature than itself can be eliminated, and problems of dimensional stability and deformation can be completely solved.

By heating the mold surface above the melt temperature, not only all kinds of surface defects of the plastic molded article are completely removed, but also the resin flow length in the mold is increased as shown in FIG. The use of a hard and hard material that is not flowable can reduce the thickness of the molded part in half and eliminate secondary ribs and bosses regardless of warpages and short shots. Thus, the unit injection pressure can be significantly reduced, and energy and equipment investment can be reduced. Ultimately, the cost of plastic molded parts can be cut in half.

Instantaneous heating mold and gas forming method using the gas fuel flame according to the present invention can be applied to all injection molding, blow molding and thermoforming. In particular, in the microcrystal injection molding method of the compact disc, the compact disc of the highest quality is manufactured by accurately reflecting the surface of the compact disc. In addition, the perfect surface of the injection-molded plastic molded part eliminates secondary processing such as spray painting to conceal the flow traces and resin but it is made by injection molding process using gaseous fuel. The problem of very rough surfaces of molded parts can be solved. In all injection molding processes, the production of a molded article with a complete surface by eliminating the secondary treatment can result in a reduction in production costs.

To date, no scientist has been able to avoid molecular structural stress in plastic injection molded parts. When the resin melted at 180 ° C. to 300 ° C. enters the mold cavity at 40 ° C., the initially filled fluid stays near the gate, after which the resin initially crosses the solidified surface to generate molecular structural stresses. do. This causes deformation and bending of the molded part after the plastic molded part itself is completely cured. However, the instantaneous heating mold using the gaseous fuel flame and the molding method using the mold eliminate all of the unpredictable parameters, molecular structural stresses and unknown problems in the injection molded article. The present invention enables the theoretical analysis of the ideal conditions of the plastic injection molding method and established the theoretical basis of the plastic injection molding method.

The invention heats the mold surface above the temperature of the molten resin, injects the molten resin onto the hot mold surface, places the first resin away from the gate and the subsequent resin near the gate, the filled resin and the mold The surface cools simultaneously. The present invention prevents the generation of resin lines, flow marks, gate marks, and rough surfaces, as well as deformation and bending due to molecular structural stresses in plastic injection molded parts, while creating a completely smooth surface.

Instantaneous heating mold using the flame of the gas fuel according to the present invention and the molding method using the same increases the flow length of the molten resin by about 30 times than the conventional method. This allows multiple gates to be located without limitation of location and form, to produce an injection molded article with a complete surface, to produce a much larger plastic injection molded article than conventional methods, and to produce very thin plastics Allow injection molded parts to be produced. In addition, by the mold for instantaneous heating using the gas fuel flame and the molding method using the same, the complicated shape and minute hole production can be easily made without a surface defect. In addition, since the flow ratio can be increased only by the mold and the molding method, it is no longer necessary to consider the fluidity in the resin, and thus it can be manufactured solely for performance such as strength or heat resistance.

The instantaneous heating mold using the gas fuel flame and the molding method using the same according to the present invention require absolutely no substances that cause side effects such as additive transition and gas marks on the mold part, that is, a material for adjusting the flowability of the resin. Do not The instantaneous heating mold using the gas fuel flame and the plastic molding method using the same can produce a high-gloss injection molded article without the problem of short-range injection without adding a high strength heat-resistant pure resin such as an engineering plastic despite the very low fluidity. have.

The instantaneous heating mold using the gas fuel flame and the molding method using the same according to the present invention have a clamping force of about 30 times smaller than that of a conventional molding machine by installing multiple gates having a flow length of about 30 times that of the conventional method. A simple injection molding machine can produce molded articles of the same size as before.

According to the effect of the above-mentioned instantaneous heating mold using the gas fuel flame and the molding method using the same, the thickness of the molded product is reduced to half, defects are reduced, and a small and simple machine and inexpensive pure resin are used. This can reduce the manufacturing cost of plastic injection molded parts by more than half. It also does not increase the time of the production process at all compared to the prior art.

Irrespective of the size of the product, the depth of the mold and the complex shape, the instantaneous heating mold and the molding method using the gas fuel flame according to the present invention is a micro-porous gas fuel supply device or a composite gas fuel employing the heating technology of the injection molding method By using a feeder, allowing gaseous fuel to burn on the mold surface, keeping the flame in contact with the other mold surface, and keeping the gas flame inside the mold, the mold surface is heated to 300 ° C. for several seconds. do.

As shown in FIG. 3, the microporous gas fuel supply device includes a fastening part 12 and a micropore part 11. The diameter of the micropores 5 is smaller than the non-flow thickness of the polymer resin, and gaseous fuel and oxygen or air pass through the micropores 5 while molten resin does not. The micro-pores 5 may be made by laser processing directly to the mold, but as shown in Figure 4, when the small micro-pores 11 are made to fix them with fasteners, complex shapes or multiple micro-pores are required. Even simple and free installation. The microcavity 11 is preferably connected to the gas fuel supply pipe 3 and the oxygen or air supply pipe (4), respectively. It is possible to connect a number of micro-pores in a single pipe or to process gas fuel and oxygen or air supply passages in the mold itself. The gaseous fuel and oxygen or air supply passages are located as close as possible to the mold surface to reduce the thickness of the mold wall to prevent leakage of heat transferred to the mold surface into the mold metal, allowing the mold surface to be heated instantaneously and efficiently. .

In consideration of the shape of the mold, micropores having a diameter larger than the non-flowing thickness of the polymer resin can be used. For example, when the micropores 5 are located outside the cavity and inside the molded article cavity, they are manufactured as moving supports entering the cavity of the molded article when the micropore mold is completely closed. That is, when it is not possible to make micropores below the non-flowing thickness of the resin, it is possible to supply gas fuel by reciprocating by connecting a gas fuel supply device of any size to the moving support. As shown in FIG. 9, when the composite gas fuel device is used, gaseous fuels may be supplied into the mold while concealing a mark on the appearance of the molded article even with a gas supply device of any size. That is, when the mold is open, the gas supply device is opened to the outside to supply gas fuel, but when the mold is completely closed, a moving support is installed to allow the composite gas supply device to enter the mold.

As shown in FIG. 2, in order to heat the mold surface as quickly as possible, the mold surface must generate a gaseous fuel flame directly to the mold surface using an internal gaseous fuel supply, and a gaseous fuel flame can be narrowed between the two molds. It is to be burned in the gap 6 and kept in a narrow space formed between the mold surfaces. At the same time, the molten resin is injected into the hot cavity after the gas fuel flame is extinguished. The interval between the extinguished gas fuel flame and the injected molten resin can be adjusted to zero by a molding method using an instantaneous heating mold using the gas fuel flame according to the present invention. The gap 6 between the two molds can be adjusted between 0 and 100 mm depending on the shape, size and other parameters of the mold.

As shown in FIG. 4, the gaseous fuel flame can be maintained inside the mold cavity, which prevents the flame from extending out of the mold and allows all gaseous fuel flames to be used only for heating the mold surface. The gaseous fuel flame held between the two molds 1 is called a closed flame as opposed to an open flame exposed to the outside air of the mold. In order to create a closed gas fuel flame and to prevent contamination of the mold surface, air or oxygen is supplied into the mold cavity 6 through micropore devices 5 and other devices mounted to the mold. The flame protects around the mold and has an appropriate shape and size depending on the size and shape of the mold.

In the modified example of the instantaneous heating mold using the gas fuel flame for easily forming a mold having a mold thickness of 15 mm or more, the cooling water for cooling the mold is rarely used, so that the gas fuel flame heating time is not increased. It is required to heat the mold as high as possible. In addition, as shown in Figure 7, the thickness of the instantaneous heating mold using the gaseous fuel flame should be as thin as possible to instantaneously heat the mold surface. In the case of using the cooling water, the cooling water pipe 7 is used as shown in FIG. 5 together with the gaseous fuel and the oxygen or air supply pipe 4. However, in order to prevent leakage of the cooling water through the micropores 5 controlled by the flow switching valve connected to the machine operated as shown in FIG. 5, the cooling water must be circulated by suction rather than by feeding. The ignition device 13 mounted at the bottom of the mold generates a gas flame between the two mold surfaces when gaseous fuel is supplied into the mold cavity as shown in FIG.

Natural gas, methane, ethane, propane, butane, pentane, acetylene, ammonia gas, or low molecular alcohol may be used as the gaseous fuel of the molding method using the instantaneous heating mold using the gaseous fuel flame, air, pure oxygen or Hydrogen dioxide can be used to make a complete oxidizing flame. Impurities due to incomplete combustion that may occur during combustion of the gaseous fuel and water generated during combustion may adhere to the mold surface and contaminate the molding, thereby supplying oxygen or air through the micropores to prevent the mold. Ensure complete combustion inside. The supply and interruption of the gaseous fuel and oxygen or air is connected to the operation of the injection molding machine to be repeatedly supplied using an electrically connected fluid conversion valve. It is also possible to use gas fuel stored in bombs or to connect city gas. As described above, when gas fuel and oxygen or air are supplied, an ignition device is installed at the lower end of the mold to connect the circuit and operation of the injection molding machine mechanically and electrically so that the gas fuel and oxygen or air are supplied and the ignition is performed. .

Instantaneous heating mold using gaseous fuel flame and molding method using the same are as follows. In the process of sealing the two molds, the gap is kept constant between the molds. Gas fuel and oxygen or air are supplied into the space 6 formed between the two parts of the mold through the gas fuel supply pipe 3 and the micropore device 5 attached to the lower part of the mold. At the same time, the gaseous fuel is ignited and the closed gaseous fuel flame is generated in the space 6 formed between the two molds, and the gaseous fuel flame is brought into contact with the surface formed in the cavity of the mold. After a few seconds, the surface of the mold is heated to the required temperature, and the mold is completely sealed between the two molds and the gas, oxygen or air supply is shut off, while the molten resin is injected into the cavity. After the cavity is completely filled with the molten resin supply, the cooling water is supplied until it is sufficiently cooled to a temperature where the resin can be taken out. After that, the two molds are opened to take out the plastic molding. As such, the plastic mold is completely produced by injection molding using the instantaneous heating mold using the gas fuel flame and the molding method using the same.

One embodiment of the instantaneous heating mold using the gas fuel flame and the molding method using the same is applied to a compact disc driver. The instantaneous heating mold using the gas fuel flame can be applied by simply changing the mold for the compact disc driver to attach the micropore device to one side of the mold. In addition, the surface of the mold is heated to the gas fuel flame to 200 ℃ to inject the molten resin. This not only improves the microcrystalline reflection of the compact disk driver memory, it also increases production by more than 50% and reduces costs by more than 50%.

Existing molds can be deformed simply by inserting the microporous gas fuel feeder and / or the multi-gas fuel feeder into the mold and heating the mold surface with a gaseous fuel flame. In addition, it is possible to improve the quality of the plastic molded article and to solve all the problems present in the molded article.

When the television housing mold is installed to have a micro-porous gas fuel supply device and a multi-gas fuel supply device, and the gas fuel flame is heated to be higher than the glass transition temperature of the resin to which the surface of the mold is applied, the television housing is made of water or traces of water. Since it does not appear, it can be used without painting, and the wall thickness can be 1.5 mm. In addition, the cost of a television housing molded product can be reduced by 30 to 50%.

Claims (4)

A gas fuel supply device for supplying gas fuel into a first space formed between the mold bodies, an oxygen supply device for supplying oxygen into the second space formed between the mold bodies, and an ignition means for igniting the supplied gas fuel and oxygen. Having a mold body; A gas fuel supply pipe connected to the gas fuel supply device and closed when fuel is supplied to the end; An oxygen supply pipe connected to the oxygen supply device and closed when oxygen is supplied to the end Instantaneous heating mold using a gas fuel flame, characterized in that comprises a. According to claim 1, wherein the supply port having a size relatively smaller than the size that the molding material can flow between the gas fuel supply device and the inner surface of the mold body and the oxygen supply device and the inner surface of the mold body is formed. Instantaneous heating mold using a gas fuel flame characterized in. The method of claim 1, wherein the gaseous fuel supply device and the oxygen supply device is formed in a slide core which can be exposed when the mold body is opened and concealed when the mold body is closed, the instantaneous heating using the gas fuel flame Dragon mold. Supplying gaseous fuel and oxygen to a space formed between the mold bodies; Igniting the supplied gaseous fuel and oxygen; Heating the inner surface of the mold body instantaneously to a desired temperature using a gaseous fuel flame; A molding method using a mold for instantaneous heating using a gaseous fuel flame comprising the steps of supplying a molding material into the inner cavity of the mold and forming the material in the mold.